A resistance random access memory (ReRAM) has thus far been proposed. The ReRAM is a memory device including a memory cell that can be switched between a high resistance state (OFF state) and a low resistance state (ON state) by means of a voltage applied. The memory cell includes a resistance change film connected between two electrodes, and changes the resistance state of the resistance change film by passing a current between the electrodes. Since the ReRAM, because of its structure, is easy to miniaturize and provides a short programming time as compared to charge storage flash memories, the ReRAM is counted on as a next-generation nonvolatile memory and is under development.
For the ReRAM, an oxygen deficiency-type ReRAM in which an oxygen-deficient portion is produced in a metal oxide film to form a current path and a metal filament-type ReRAM in which a metal filament is deposited in an insulating film to form a current path are proposed. The oxygen deficiency-type ReRAM needs a certain level of current in order to change the resistance state of the resistance change film, and therefore has difficulty in current scaling necessary for miniaturization. In addition, since the interconnection resistance increases with miniaturization, the effect of the RI drop during current passage (the voltage drop) increases to make circuit operations difficult. On the other hand, in the metal filament-type ReRAM, metal ions are diffused and precipitated in an insulating film to form a fine line of the metal in the insulating film, and a low resistance state is thereby obtained. Thus, operations at low current are possible as compared to the oxygen deficiency-type ReRAM, and the number of fine lines decreases with miniaturization; therefore, current scaling in accordance with miniaturization is possible.